Comparison effort is good and informative... but I repeated the same test on a whole range of CPU, VGA and RAM configurations. Coincidentally test cases included a QX9300 CPU and a Q9400 CPU. It turned out that :
a ) Single Core i7-860 and Corei7-870 CPU s have the same times as reported in this review - furthermore, with MultiThreading enabled, there was a slight drop in performance ( around 0,3 %) compared to Multithreading disabled case.
b ) Higher clock speeds lead to higher performance.
My review is Turkish, but you can download the raw pdf data too and compare the results.
http://www.muhendispc.com/index.php?option=com_content&view=article&id=106:pm2010perf&catid=43:powermill&Itemid=94